Tonimus's L1 Madcow Patriot build "FINISHED!"

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Tonimus

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Making the Level one cert leap. Dunno when I'll actually attempt the flight as yet. With Madcow's Black Friday sale, I bought a 4" Patriot with all the options. 54mm motor mount too.

Unbagging:


First I lopped the bottom off of the nose cone to put a bulkhead inside the shoulder. I also enlarged the fin slots and test fitted the fins.


I then peeled all the glassine off of the motor mount. Came off in one solid piece with a little patience.


Sanded down a 54mm to 4" centering ring to fit inside the nosecone shoulder. I added t-nuts and used an inner coupler bulkhead for the eye bolt. I decided to make the nose weight adjustable, since I plan on flying lots of different motors in it. I don't want it terribly over stable and heavier with smaller motors.


And all bolted into the nose.


Sanded all the glassine off of where the fin fillets will be.


Tacked two centering rings in place on the motor mount. Aft centering ring will be epoxied in after internal fillets get done.


I have no idea where I put my epoxy, so I'm done for tonight. I'll be headed out tomorrow to get some more.
 
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FYI: unless that is a fiberglass nose cone, epoxy will not stay stuck. for the non fiberglass nose you will have to use a mechanical fastening to keep your nose assembly in place.
Rex
 
FYI: unless that is a fiberglass nose cone, epoxy will not stay stuck. for the non fiberglass nose you will have to use a mechanical fastening to keep your nose assembly in place.

It's not fiberglass, but it will hold. I used PC Auto Bond epoxy for it, with which I've had really good luck bonding stuff to plastics. If for some reason I do have a failure, only the nosecone itself will work loose, as the weight is part of the eyebolt assembly. With the length of the eyebolt assembly and the coupler being past the shoulder, it can't physically come off unless it splits.

Were the e-matches part of the madcow sale?

Haha, good eye. No, they were not, just arrived at the same time, so they ended up in the picture.
 
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Screwed up and put fillets on the fin side of the middle centering ring. Notched the fin tabs and have half of the internal fillets setting.

 
And now I'm out of epoxy again. Brilliant. still have 6 fillets on the inside left to do, then the rear centering ring. I'm waiting on a replacement bulkhead from Madcow, as they missed one of the larger bulkheads I was supposed to get with the AV bay. Motor retainer and fillet clay are coming from Apogee. Should be done, except for paint, before Christmas.
 
My large AV bay bulkhead came from Madcow yesterday, so I glued it to the smaller one. Test fit it this morning, and both outer bulkheads were just a touch off. I must not have had them aligned perfectly. Oh well. They were maybe 1mm off on one side. So I marked it and got to sanding. Here they are, fitted and ready to go.


Sled glued up and drying:


I got the last of my parts from Apogee today, so she should be fully built by Monday. Then much finishing work is ahead...

EDIT: Anyone following along should note that I ordered the following extras from Madcow when I got the kit.

2 extra 54mm to 4" centering rings
1 extra 4" coupler bulkhead
 
Got the last of the internal fillets done, rear centering ring on, and the Aeropack retainer on.


Decided to make a 29mm motor mount adapter too.
 
Lately I've been laying down a JB Weld coating around the rear centering and filleting the centering ring to the body tube. I find it eliminates the need for painting that area with High Temperature paint (BBQ or header).

Nice build you've got going on here.
 
Lately I've been laying down a JB Weld coating around the rear centering and filleting the centering ring to the body tube. I find it eliminates the need for painting that area with High Temperature paint (BBQ or header).

Nice build you've got going on here.

Why, thank you, Sir. I'll probably do that after I get my Fix-it epoxy fillets done. Here's a pic with the adapter in place with a spent 29mm I had in the box:
 
Why, thank you, Sir. I'll probably do that after I get my Fix-it epoxy fillets done. Here's a pic with the adapter in place with a spent 29mm I had in the box:


Fix it epoxy clay fillets? That stuff is brittle and doesn't bond really well. I would recommend you go with real epoxy fillets if your going to fly it on 54mm motors and because it is your cert and you don't want anything to break,
 
Looks like its coming along nicely. Gotta love the design of the Patriot.
 
Fix it epoxy clay fillets? That stuff is brittle and doesn't bond really well. I would recommend you go with real epoxy fillets if your going to fly it on 54mm motors and because it is your cert and you don't want anything to break,

Inside the centering ring is regular epoxy. I wanted to use fix-it clay for aesthetic reasons. The inside is plenty strong enough I could run it without an external fillet. Makes a nice transition to the body tube and easy to shape nicely for the fins.
 
Fillets on and primary shaping done.


Fillets sanded down and fin edges sealed with CA.


Outside of the rocket is done except for drilling rivet holes for the AV bay. I'll probably tackle the aft centering ring fillet tonight, along with drilling the holes for the rail buttons.
 
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Inside the centering ring is regular epoxy. I wanted to use fix-it clay for aesthetic reasons. The inside is plenty strong enough I could run it without an external fillet. Makes a nice transition to the body tube and easy to shape nicely for the fins.

Ok as long as the internals are nice and strong your fine. Looking great so far. I never could master the epoxy clay fillets mine would always turn out lumpy and uneven.
 
Just saw the thread so I had to catch up but looks great! What you plan to fly it on for your cert?
 
Just saw the thread so I had to catch up but looks great! What you plan to fly it on for your cert?

Haven't made up my mind yet. Many, many options. I'll probably go something in a 54mm flavor, as I've already got a CTI 3G case.
 
Ok as long as the internals are nice and strong your fine. Looking great so far. I never could master the epoxy clay fillets mine would always turn out lumpy and uneven.

When I applied the fillet, I used the back end of a Sharpie to remove the bulk of the material and do the primary shaping. Excess was removed with a hobby knife as a scraper. After about 6 hours, when it was set up, but still easy-ish to sand, I used the handle from my hobby knife (without the blade) as a sanding block to sand them down with 400 grit sandpaper. They'll get a thick coat of self-etching primer and sanded down again.

The fillet on the rear centering ring was smoothed out first with a gloved finger. This distributed the clay pretty evenly. I then dipped my gloved finger in 90%+ alcohol and smoothed out the fillet. This got out the last of the bumps and smoothed it out nicely, in my opinion.
 
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Your epoxy clay fillets turned out way better than mine did.

You can also use it to fill the grooves in the airframe. Apply, force in and scrape off with a razor blade, and lightly sand when cured.
 
Your epoxy clay fillets turned out way better than mine did.

You can also use it to fill the grooves in the airframe. Apply, force in and scrape off with a razor blade, and lightly sand when cured.

I saw that technique on Apogee's website. I'm not sure I really trust it to hold with as thin as the spirals on the Madcow tube are. I think I'll just prime the hell out of it.

I let the Fix-it clay cure overnight, coated it with JB weld for ease of cleanup and heat resistance this morning, per o1d_dude's advice.
 
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I did it on my Vertical Assault and I found it easy and worked well. Lots of people on here use Bondo or something similar. Others use filler primer, so you are not alone.
 
Upper rail button t-nut installed and JB weld is curing:


Lower rail button screwed into the aft centering ring:
 
I got the rivets that hold the AV bay to the payload section installed. After viewing it on the computer, it's just parallax from taking the picture that makes the rivets seem out of line. I drilled for a total of 4 rivets and 2 shear pins for the nose cone.


Aside from paint, the only thing I have left to do is figure out the layout of the AV bay internals and where I want to drill my vent holes.
 
500# swivels are on their way here, then I'll order a couple of Onebadhawk's kevlar harnesses on Wednesday... I've already got a bunch of 2' parachutes, a 3' parachute, and a 6' I inherited. A little odd that they are all red with white lines. Anyway, priming starts Thursday!
 
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